To control dandelion, plantain and clover in the fall, apply Organic Weed Control as soon as the summer heat stress is over or when daytime temperatures are no longer reaching into the 90’s. That will vary from year to year and vary by location. For some, it could be as early as mid-August. September 1st would be fine for most areas to suppress the seeds that would have sprouted in the next generation. Note that you cannot overseed in the fall if you apply Organic Weed Control.